1. Field of the Invention
The present invention relates to a work transfer apparatus that carries a plate-shaped work in a vacuum, for example.
2. Description of the Related Art
A conventional transfer apparatus for carrying a plate-shaped work is described in Japanese Laid-open Patent Publication No. 2007-118171, for example. The work transfer apparatus taught by this document includes a fixed base, a pivotal base supported by the fixed base, a lifting base supporting the pivotal base, a ball screw slide mechanism that vertically moves the lifting base, a link arm mechanism supported by the pivotal base, and a hand supported by the link arm mechanism.
The hand and the link arm mechanism are located in a vacuumed chamber, while the fixed base is located in a space outside of the chamber, exposed to the atmospheric pressure. Inside the fixed base are provided various driving motors such as a motor for rotating the pivotal base and a motor for driving the link arm mechanism. The conventional work transfer apparatus is employed to carry a work heated to high temperature, and the radiant heat from the work may affect the peripheral components. In light of this, the link arm mechanism, which is exposed most to the radiant heat, is provided with a coolant circulation path for cooling the peripheral components.
In the foregoing work transfer apparatus, the various driving motors are arranged in the fixed base so that they are in an atmospheric-pressure space. By this arrangement, however, the fixed base tends to be large, and hence the overall size of the transfer apparatus is also large.